Regulating device for electromagnetic driven vibratory pendulums



Jan. 3, 1950 c. F. AHLBER'G 2,493,101

REGULATING DEVICE FOR ELECTROMAGNETIC DRIVEN VIBRATORY PENDULUMS Filed Oct. 23-, 1945 T E r e I55 5 ak Patented Jan. 3, 1950 UNITED "STA-res T OFFICE i w REGULATI NG (DEVI-CE assessments.- A NETIC DRIVEN vIBnA'ronY: PEN UnUMS Curt Fredrik .Ahlb erg, App'elvikcn, s edenlla signont'o Telefonaktiebola get L M "Ericsson, Stockholm, Sweden, acqrnpany of Sweden Application October;23, registrar No. 623,949- In Sweden November 18, 1944;

By vibratory pendulums, which are driven by electromagnetic self interrupters supplied from a source 'ofdire'ct' current, there is the'drawback thatthependulum, by variation of the working voltage, changesits amplitude and consequently its frequency -and impulse-ratios The term impulse-ratio has reference to the ratio between the time-during" which the contactus-closed and the time during which this sameco'ntactis open. Owing to this, vibratory 'pendulums have not been used in many fields, in which the otherwise good properties of said pendulums could assert themselves: 'Asan example of such a field converters of the vibratory type may be mentioned, especially for great loads. By such converters it is as a rule of great importance that the method of operation of the contacts, characterized by frequency and impulse-ratio, should be kept constant by varying working voltage. By motor driven contacts this can be done by known means for keeping the number of revolutions of the motor constant, but with contacts, driven by means of a pendulum it has not until now been possible to eliminate the changes in frequency and impulse-ratio by variation of the working voltage. Furthermore, these changes do not take place continuously by continuous change of the working voltage, but the pendulum runs through several stable and unstable conditions of oscillation, thereby lingering in the stable conditions and passing by leaps through the unstable ones. The pendulum therefor works unreliably and is unfit for the purpose of being a contact converter.

The present invention relates to such vibratory pendulurns wherein the voltage for operating the pendulum is supplied from a condenser and the invention will now be described with reference to the drawings in which Figs. 1 and 2 are diagrammatic views of circuit-arrangements embodying the invention, and Fig. 3 is a circuit diagram showing the invention applied to a contact converter.

Referring to the drawings an electromagnet is shown at M for the pendulum P. A switch is illustrated at b which is adapted to be closed by movement of the pendulum and opened during reverse swinging movement of the pendulum. A further contact is carried by the pendulum P adapted for controlling a circuit extending from a condenser C. An armature A is carried by the pendulum and the armature is operated by the electromagnet M.

The operating voltage for the electromagnet M and accordingly for the pendulum is supplied 3 Claims. (01. ea-152m irom the condenser C. The condenser is charged 2, throu h airesistor Rffrom asource'ofoirect current indicated at The voltage of the source of current E is assumed to vary. r r c The condenser C ,is discharged over a resistor R1 when the contact it, engages the associated contact and duringthe make-interval of the switch k. Itwill be observed thatthe discharge Ofjhje condenser eXtends cveralcnger period when the switch, P; remains, closed. over, ,a, longer period. Should the voltage across the, source, 'Ejincrease and accordingly the voltage, across the condenser Cv will increase and the. pendulum will thereby increase, its amplitude ,and consequently the switch It will increaseits impulse-ratio. In other words, the interval in which the contacts at k are closed increases and consequently the discharging time for the condenser also increases. Thus the voltage across the condenser C decreases and the voltage in the interval during which the contacts in are closed will hereby within large limits be independent of the voltage of the source E. The magnetic driving power of the electromagnet M on the armature A, and herewith the amplitude of the pendulum, will thus be almost constant.

Fig. 2 shows another simple embodiment. The regulating contact k is here made as a breakcontact which, during intervals, the length of which depends on the amplitude of the pendulum, breaks the current supply to the condenser C. Thus a stabilizing effect on the condenser voltage is obtained, and also a nearly constant amplitude for the pendulum.

Fig. 3 shows another application of the embodiment according to Fig. 2 in a contact converter for converting direct current of one voltage into direct current of another voltage.

The contact converter, containing the transformers TI and T2, the condensers C1-C4 and the contacts Isl-4:6, is connected to the same source E of current as the pendulum, and the pendulum operates, besides the self-interrupter contact b and the regulating contact 70, also the movable contacts kl and M 01 the converter. A load B is supposed to be connected to the tapping terminals W.

A condition for sparkless breaking and making of all the contacts Isl-Jet is, that the oscillatory circuits formed by the condensers and the windings of the transformers are tuned in a certain way in relation to the frequency and impulseratio of the contacts. Hitherto this condition has been filled only by a certain constant working voltage E; with a pendulum according to the invention, however, such conditions can be filled also by variable working voltage E, since the frequency of the pendulum and so the frequency and impulse-ratio of the contacts kl and k4 become constant.

The invention may of course be applied to other technical fields where it is important that the member controlled by the pendulum should have constant frequency.

I claim:

1. In combination, a vibratory pendulum, a controlled electromagnet for vibrating said pendulum. a condenser, a source of direct current, a resistor, a circuit containing said resistor and said source connected in parallel to a discharge circuit for said condenser including said electromagnet and a contact operated by said pendulum for alternatively energizing and deenergizing said electromagnet, a further contact included in a circuit containing said condenser and being adapted to be operated by said pendulum in one of its end positions, and to control the condition of charge of said condenser in dependence on the ratio between the time during which said further contact is closed and the time during which it is broken.

2. In combination, a vibratory pendulum, an electromagnet for vibrating said pendulum, a condenser, a source of direct current, a resistor, a circuit containing said resistor and said source connected in series, said circuit and said condenser being connected in parallel to a discharge circuit for said condenser including said electromagnet and a contact operated by said pendulum for alternatively energizing and deenergizing said electromagnet, a further discharge circuit for said condenser including a further contact adapted to be operated by said pendulum in one of its end positions and to close said discharge circuit during a moment, the length of which depends upon the ratio between the time during which said further contact is closed and the time during which it is broken.

3. In combination, a vibratory pendulum, an electromagnet for vibrating said pendulum, a condenser, a source of direct current, a resistor, a circuit containing said resistor and said source connected in series, said circuit and said condenser being connected in parallel to a discharge circuit for said condenser including said electromagnet and a contact operated by said pendulum for alternatively energizing and deenergizing said electromagnet, a further contact included in said first mentioned circuit and being adapted to be operated by said pendulum in one of its end positions and to break said first mentioned circuit for a moment, the length of which depends upon the ratio between the time during which said further contact is closed and the time during which it is broken.

CURT FREDRIK AHLBERG.

REFERENCES CITED The following references file of this patent:

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